Imaging appearance of diffuse neurofibroma

OBJECTIVE. The purposes of this study were to describe the imaging appearance of diffuse neurofibroma in 10 patients and to summarize demographic data on a large group of patients. MATERIALS AND METHODS. Retrospective review of the pathology and radiology teaching databases at two institutions yielded the cases of 339 patients with a pathologic diagnosis of diffuse neurofibroma. Diagnostic-quality images were available for 10 patients. Images from MRI (n = 8), CT (n = 5), and sonographic (n = 1) examinations were evaluated for lesion location, size, depth of involvement, growth pattern, and intrinsic signal intensity, attenuation, or echogenicity. Demographic information, associated lesions, and tumor location were recorded for all patients. RESULTS. Among 10 patients with images, eight of whom had neurofibromatosis, diffuse neurofibroma involved the skin and subcutaneous tissues (n = 9) and frequently extended to the fascia over muscle (n = 6). Plaquelike (n = 5) and infiltrative (n = 3) growth patterns were most common. One lesion had a mixed growth pattern. Prominent internal vascularity was common (n = 5). MRI signal intensity and CT attenuation were typically nonspecific. Enhancement was intense in all five patients with contrast-enhanced MR examinations. Including patients with and those without images, 349 diffuse neurofibromas were present in 339 patients. The mean patient age was 35.1 years. Lesions involved the extremities (n = 120), trunk (n = 122), head and neck (n = 98), and deep structures (n = 9). CONCLUSION. Diffuse neurofibroma frequently grows as a plaquelike or infiltrative lesion involving the skin and subcutaneous tissues. Prominent internal vascularity is common. There is a much wider soft-tissue and age distribution and association with neurofibromatosis than previously reported.